Spellslinger mage bullet enhancement question

OK:

". As a swift action, he can sacrifice a spell and transform that energy into a weapon
bonus equal to the level of the spell sacrificed on a single barrel
of his firearm. With that weapon bonus the spellslinger can
apply any of the following to his arcane bond: enhancement
bonuses (up to +5) and dancing (snip long list)"

So if you sacrifice a level 1 spell, can you take something with a +1 value like Shock or Flaming, without a +1 enhancement value first? Getting +0 flaming bullets?

Or does a regular +1 enhancement need to be put on first, requiring 2nd level spells for a +1 Flaming or Shock effect on the gun?

Also, is there an official Spellslinger FAQ? I can't seem to find one anywhere.

While it does not specify that it requires the +1 enhancement bonus first, it also does not specify that it does not (as Amulet of Mighty Fists does).

With no text either for or against, we resort to the default rules for magic weapons, which includes the text:

A weapon with a special ability must also have at least a +1 enhancement bonus.

So in order to get something like Flaming or Shock on your gun, you must either sacrifice a 2nd level spell or you must have a +1 gun as your bonded gun to begin with.

What if you cast Magic Weapon on your gun and then sacrifice another spell for something like Shock or Distance? At level 1, it'd give you one minute of really good firepower.